1. Field of the Invention
The present invention relates to an improvement to the composition for preventing ageing of the skin, which is the subject of patent PCT/FR 97/02017, filed on Nov. 10, 1997 in the name of the Applicant.
The invention similarly applies both to natural ageing and to phenomena of accidental ageing of the skin due to the manifold attacking factors to which the skin is subjected daily, in particular solar radiation. 2. Description of the Prior Art
In general, it is known that free radicals (aggressive particles possessing a free electron) are the main agents incriminated in skin damage caused, for example, either by prolonged exposure to solar radiation and thus to the ultraviolet rays included in this radiation, or even by metabolic and enzymatic reactions which take place in the body.
Radical attack initiates chain reactions which stop only when two free radicals become mutually inactivated.
Lipid peroxidation (lipoperoxidation) is a typical case of a radical-induced chain reaction.
Oxidation of the membrane lipids results in the formation of lipoperoxides, which decompose into various fragmentation products, some of which are highly aggressive.
One of the most important and most aggressive fragmentation products is an aldehyde, malondialdehyde (MDA), which exhibits formidable toxicity by transversely bridging proteins, intracellular lipids and DNA.
It thus appears that the free radicals and the cascade of chain reactions to which they give rise in the body play a very important role in the process of ageing of the skin.
With the aim of combating this radical action, the Applicant proposes a composition which uses the properties of Chrysanthellum indicum indicum, which, according to the abovementioned French patent:
has very good radical-scavenging properties, so as to obtain anti-ageing action both for natural and accidental ageing; PA1 ensures effective protection against the reactions leading to the production of OH.degree. radicals or radicals of oxoferryl type; PA1 reduces the fall in the ATP content of the keratinocytes after irradiation, so as to obtain a repairing effect. PA1 a dark brown coloration which causes the skin to be treated and that of the fingers used to carry out the application to be dyed an intense mustard-yellow colour. The strong intensity of this dyeing is attenuated on rinsing, but leaves a dark yellow coloration after washing. PA1 Poor stability over time: a concentration of water in the bottom of the container and considerable release of oil at the surface are observed from 24 hours onwards. PA1 A strong odour of plant extract. PA1 a) either weaker activity than addition of the activity of each of the products, on account of an antagonistic effect (one product reducing the activity of the other) or of a saturation effect (impossibility of exceeding the maximum effect reached) or even a harmful effect (predominant antagonistic effect); PA1 b) or an activity which is equal to the sum of the activities of each of the products tested separately; PA1 c) or to higher activity than the sum of the activities of the products tested separately (synergistic effect). PA1 d) PA1 on the one hand, to measure the effects of four compounds: PA1 on the other hand, to investigate any potentiation between Chrysanthellum indicum and one of the other compounds. PA1 Protection=(100-release of pentane) Total protection=100 PA1 No protection=0 PA1 Synergistic effects (gain in protection observed ranging from +34% to +182% relative to an additive effect). This synergistic effect is observed in several cases (various concentrations of Chrysanthellum indicum and of combined extracts) and is particularly outstanding in the case of a combination with green tea. Such synergistic effects are noteworthy. PA1 Total or partial additive effect. Given the very good results obtained with Chrysanthellum indicum alone, and given the existence of a threshold of maximum efficacy, it was not obvious that additive effects could be obtained. Total or partial additive effects were, however, obtained in various Chrysanthellum indicum/other radical-scavenging substance combinations, which, here also, is quite noteworthy. PA1 prevent ageing of the skin and repair the damage caused by radical attack on the skin, PA1 protect and repair hair exposed to damage caused by ultraviolet rays and other environmental attacking factors which generate an excess of free radicals. PA1 a plant extract which is rich in phenolic compounds, PA1 a plant extract which is rich in carotenoids, PA1 a plant oil which is rich in tocopherols, PA1 an antioxidant of natural or synthetic origin, PA1 an enzymatic system for trapping free radicals.
Hitherto, as many scientific publications affirm, the studies carried out on Chrysanthellum indicum revealed the clinical effects in essentially circulatory and digestive pathologies (exclusively medical field).
Only French patent No. 87/10502 proposed a cosmetic composition comprising an extract of Chrysanthellum indicum containing from 1% to 10% extract of Chrysanthellum indicum, for applications such as shampoos and hair lotions, dermal emulsions, body milks, lipsticks or even cosmetic compositions in the form of aerosols.
Besides the fact that that document does not mention the prevention of ageing of the skin, the concentrations recommended therein give products which are entirely inappropriate and even incompatible with normal cosmetic use, since, at these concentrations, emulsions for topical use exhibit, in particular: